1. Field of the Invention
The present invention relates to a heat exchanger in which different core portions are integrated with each other, and more particularly the present invention relates to a heat exchanger which can be effectively applied to a radiator of an automotive engine and a condenser of an automotive air conditioning apparatus.
2. Description of Related Art
Conventionally, an automotive air conditioning apparatus is assembled into a vehicle at a car dealer or the like after the vehicle has been completed. Recently, however, the automotive air conditioning apparatus is generally installed in the vehicle during vehicle assembling process. Therefore the automotive air conditioning apparatus is assembled with automotive parts in the assembling process of the vehicle at the manufacturing plant.
A heat exchanger in which different core portions such as a radiator and a condenser are integrated is disclosed in Japanese Patent Publication No. 3-177795. In this heat exchanger, cooling fins of first core portion and second core portion are integrated with each other. These cooling fins are connected to each oval flat tube of the first and second core portions by brazing.
In the cooling fin, a plurality of slits are formed at the center portion between the first and second core portions for interrupting a heat transmission from a high temperature side core portion (for example, radiator core portion) to a low temperature side core portion (for example, condenser core portion).
The required heat exchanging abilities of the first core portion (condenser core portion) and the second core portion (radiator core portion) varies in accordance with the difference of engine type or vehicle type despite the required constitutions of the heat exchanger are the same. When the automotive heat exchanger is constructed by some single heat exchangers, the required heat exchanging abilities thereof are set by tuning fin pitches of the cooling fins respectively in accordance with the engine type or vehicle type.
However, in the heat exchanger in which different core portions are integrated and cooling fins of first core portion and second core portion are integrated with each other, each fin pitch cannot be designed independently respectively. Therefore, the above-described method of setting the fin pitches in the first and second core potions respectively cannot be applied to this type heat exchanger.